The relationship between iron status and lead absorption in rats.

The absorption of lead from loops of small intestinein situ was investigated in rats in which iron absorption was increased by stimuli varying in type, intensity, or duration. Lead absorption was increased by a short period of severe iron restriction before any change in hematological indices became apparent. A period of hypoxia, which markedly increased iron absorption, did not influence absorption of lead. An extended period of moderate iron restriction resulted in a marked reduction in liver iron stores and increased iron absorption throughout the 17-wk experiment. Under these conditions lead absorption was initially also increased, but after 12 wk, when iron intake had become adequate to meet essential requirements, lead absorption was similar to that in iron-supplemented rats. These results are discussed in the light of evidence for a receptor-mediated absorption process for iron.